High‐Performance Polymers for Membrane CO₂/N₂ Separation

This Concept examines strategies to design advanced polymers with high CO₂ permeability and high CO₂ /N₂ selectivity, which are the key to the success of membrane technology for CO₂ capture from fossil fuel-fired power plants. Specifically, polymers with enhanced CO₂ solubility and thus CO₂ /N₂ selectivity are designed by incorporating CO₂ -philic groups in polymers such as poly(ethylene oxide)-containing polymers and poly(ionic liquids); polymers with enhanced CO₂ diffusivity and thus CO₂ permeability are designed with contorted rigid polymer chains to obtain high free volume, such as polymers with intrinsic microporosity and thermally rearranged polymers. The underlying rationales for materials design are discussed and polymers with promising CO₂ /N₂ separation properties for CO₂ capture from flue gas are highlighted.